FIGS. 1A and 1B show a conventional UV lamp system which employs a cavity. The UV lamp system 10 includes a microwave or RF wave energy source 11, for example, a magnetron, a waveguide 12 and a cavity 13. In the cavity 13, a UV lamp 14 is disposed. In FIG. 1, two UV lamps are arranged in a housing 15.
The microwave energy generated by the magnetron 11 is supplied to the cavity 13 thorough a waveguide 12. Inside the cavity 13, the microwave energy is coupled with the UV lamp 14, and excites one or more elements contained in the UV lamp (for example, Hg), thereby the UV lamp emits UV light including, for example, light of D line wavelength (365 nm).
As shown in FIG. 1B, two UV lamps 14 having a two-inch (5 cm) length are used so as to obtain a wide light irradiation area of about 6-inches (15 cm) in length. However, longer length lamps 14 can be utilized depending on applications of the UV lamp system.
Recently, a new type of UV lamp that does not require a cavity has been developed. For example, U.S. Pat. No. 7,095,163 describes one example of the cavity-less UV lamp. The entire contents of U.S. Pat. No. 7,095,163 are incorporated herein by reference.
FIG. 2 shows a schematic view of the UV lamp disclosed in U.S. Pat. No. 7,095,163. The UV lamp 20 includes a coaxial glass bulb 21 inside of which Hg vapors and Ar gas are enclosed, and an antenna 22 as a microwave coaxial probe. Microwave energy (MW) is supplied through the antenna 22 so as to excite Hg vapor enclosed in the glass bulb 21 to radiate ultra violet (UV) radiation.
However, the UV lamp of U.S. Pat. No. 7,095,163 has several problems. For example, the length of the glass bulb 21 is limited to about λ/4, where λ is a wavelength of the microwave energy. When the wavelength λ is 2.45 GHz, λ/4 is about 3 cm.
Further, as shown in FIG. 2, since the antenna 22 is straight, the arrangement of the UV lamp 20 inside a housing is limited.
The teachings herein alleviate one or more of the above noted problems with a UV lamp including a UV lamp unit and an antenna lead having a bent portion.